Researchers investigate how some bats survive with white-nose syndrome

April 11, 2012

LEWISBURG, Pa. — Two Bucknell University biologists are leading an investigation into how and why some bats survive - and others die - when exposed to the tell-tale fungus that causes white-nose syndrome.

Associate Professors of Biology DeeAnn Reeder and Ken Field have received a two-year, $481,000 grant - including $289,000 from the U.S. Fish & Wildlife Service plus matching funds from Bucknell to find out whether certain genetic characteristics, behavior and environmental factors contribute to the severity of the disease, which has killed up to 6.7 million bats in eastern North America. || See related news release

"This new grant allows us to really look at who has survived and why," said Reeder, who has received more than $1.2 million from various agencies to study white-nose syndrome during the past four years. "There are basically three choices: The survivors have gotten lucky and were never exposed, which is bad news because it means they will eventually be exposed. Or, there are things about them that make them resilient to exposure. Or, they have been exposed and are immunologically resistant."

Disease spreading quicklyWhite-nose syndrome is killing bats at an alarming rate. In Pennsylvania alone, an estimated 95 percent of the bat population has been wiped out, and the disease is quickly spreading across the country. In October, a team of scientists including Reeder identified Geomyces destructans as the deadly fungus that causes white-nose syndrome in bats, a critical milestone in the effort to prevent extinction. || See Bucknell news story and video || See also paper in Nature

Field for the past three years has been involved in a project to develop measures for immune function in bats. The goal of his work is to better understand how hibernation affects immune competence. Specifically, he seeks to find out whether periodic arousal - or waking of bats during hibernation - maintains their immune responsiveness through extended periods of hibernation.

Narrowing the causeThe latest study, to be conducted in Reeder's and Field's laboratories at Bucknell and in the field, is a next step in determining how - if possible -- to increase the chances for survival and of fending off the disease among various bat species. Reeder and Field will work in collaboration with researchers at the U.S. Fish & Wildlife Service, Pennsylvania Game Commission and wildlife organizations in Illinois, New York state, Virginia, Rhode Island and Michigan.

As part of the study, little brown bats, one of the species most affected by white-nose syndrome, will be exposed to varying amounts of Geomyces destructans to determine how resilient and resistant they are to infection with the fungus. Some bats will not be exposed. The study will seek to find out how much of the fungus is necessary for infection and how much the bats can tolerate in environments of varying temperatures. The researchers surmise bats that hibernate in colder temperatures have a stronger likelihood of survival.

The study also will examine how traits such as body fat content, hibernation preferences and behaviors contribute to survival. For example, little brown bats that go into hibernation with more body fat and mass seem to be less likely to develop severe infections.

Ongoing researchWhite-nose syndrome was discovered in hibernating bats in the winter of 2006 by a state wildlife biologist and cavers in the state of New York. It since has spread throughout New England and into the Mid-Atlantic states. Reeder, an ecophysiologist, became involved in the research in 2008. She studies the hibernation patterns of bats in her laboratory at Bucknell.

Six species of bats have been affected so far. Bats are beneficial to the ecosystem in part because they eat a significant number of insects, including disease-ridden mosquitoes and crop pests.

Bats with white-nose syndrome have been found dead or starving, flying erratically during the day and in cold temperatures, weeks before they normally emerge from hibernation. Not all of the infected bats have visible white fungus. Other symptoms include extreme weight loss, depleted fat reserves or the inability to awaken from hibernation.

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